This project will produce an optical range of motion measurement and biofeedback system which is portable, passive and cordless. This system will speed up the recovery of people in rehabilitation after orthopaedic surgery or illness. The system transmits short pulses of lights which are reflected back by three reflectors worn by the user. A camera measures the position of the range of motion and displays it. The computer also guides the user to follow a predetermined training program and records all data, including statistical averages. Phase I tests the feasibility of the range of motion system for use in rehabilitation: 1) develop a system which measures the range and speed of motion the rehabilitating person has over his or her injured body part; 2) build cordless prototypes of this system; 3) implement a clinical test program, which works directly with professionals and users in rehabilitation. Phase II facilitates the full scale adaptation of this device through development of a stand-alone, battery-operated version of the system and through refinement of the system based on clinical trials with many clients in selected rehabilitation centers.